Starfish Cactus Stapelia grandiflora

The Starfish Cactus or Starfish Flower is a leafless, succulent herbaceous perennial from South Africa in the dogbane family (Apocynaceae). Its native habitat is the desert or arid shrubland. It is a cactus-like plant and has large showy starfish-shaped flowers. Although the plant is called the Starfish Cactus, it is not a cactus.

This plant forms a large compact cluster of stems up to 1.75 feet in diameter. The stems are four-angled, erect, 4 to 12 inches long, and about 1 to 1.6 inches thick. They appear soft, velvety, pale green to reddish, and have upright hooked tubercles along the ridges. The tubercles are small protuberances, but they are not prickly. Its flowers bloom in late summer to fall at the base of the plant. The flower buds look like an inflated balloon, but when they open they are star-shaped flowers. Its flowers are large, 6 to 8 inches wide, flat, deeply lobed, starfish-shaped in shades of reddish-brown to purple. The flower is malodorous and smells of rotting meat which makes them attractive to flies. The flies pollinate the flowers, then long, thin seed pods or follicles are produced. The seeds are very slow to ripen and may take up to 1 year. Upon maturity, the pods open. The seeds are attached to silky-like plumes that are scattered by the wind.

The Starfish Cactus thrives in full sun to partial shade, but it prefers partial shade in very hot climates. Select a growing medium that is recommended for cacti or succulents that will drain well and has a neutral pH. Well-drained soil  is required and overwatering needs to be avoided. It is best to allow the growing medium to dry out between waterings. This plant is winter hardy in USDA Plant Hardiness Zones 9 to 11. If planted outdoors, be sure to bring it inside before temperatures drops below 40 degrees Fahrenheit. This plant likes to be rootbound; therefore, repotting may be needed about every 2 to 3 years.The plant may be propagated by seeds or stem cuttings.  

The Starfish Cactus requires minimal care. Consider this plant as an ornamental for a table, window sill, or hanging plant. If planted outdoors, consider planting in rock garden  or succulent garden. It is drought and poor soils tolerant. 

Insects, Diseases, and Other Plant Problems:  Mealybugs are the main pest for succulent plants. Monitor for mealybugs, stapeliad snout beetles, and aphids. Overwatering that can result in root rot and rotting stems. If the odor from the flowers is intolerable indoors, some gardeners recommend moving the plant outdoors during the summer months during blooming.